I've always left my Amp on the DD/DTS setting with THX turned OFF. The advent of PLII & Logic 7 enhancements to ProLogic tracks has got me thinkinging about the DSP modes on my Denon AV-A10SE. Does anyone use the DSP modes for PL sources? I remember reading somewhere that the THX button will result in pseudo stereo surrounds, and the descriptions of the Widescreen & Matrix DSP modes may be interesting. I'll be doing some testing myself at the weekend, but I'd really like to hear the experiences of others. Mark.